Eagle QuickTip: Teardrops

If you have to work on a particularly dense board, you can’t really get away from using small vias: <=0.3mm/12mil drill bits and <=0.125mm/5mil annular rings.  While unavoidable, using small vias and particularly small annular rings poses a problem during manufacturing, since there is inevitably some variability with the drill placement and the smaller the annular rings (the metal ring left around the drilled hole) the more likely you are to end up with a broken via.  One easy solution to improve your yield of error-free boards is using something called ‘teardrops’.  They fan the trace out before it joins the via, making a ‘teardrop’ shape, effectively increasing the size of the annular ring and reducing the risk of faulty vias.

Most packages include some means to create teardrops, and Eagle is no exception.  The default installation includes a ULP called ‘teardrops.ulp’, which you can run by simply typing ‘ULP teardrop’ when your board file is open.  One word of caution, though … you should only run the teardrop ULP on a seperate, renamed copy of your board file since the changes are irreversable!.  Make a copy of your board names xxx_teardrops.brd, make sure the original schematic is closed, and then run “ULP teardrop”.  Give it a try and you should get an idea of why they can be useful on tight-pitch boards like the image above, which was from a 6mil/6mil 4-layer board with 0.3mm drill holes and 0.1mm annulars.


Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.

Join 7,500+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython in 2018 – Python on Microcontrollers is here!

Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Follow Adafruit on Instagram for top secret new products, behinds the scenes and more https://www.instagram.com/adafruit/

Maker Business — Despite multiple bankruptcies, RadioShack continues to find ways to keep the lights on

Wearables — Molding with glue

Electronics — A few words on inductor resistance

Biohacking — Running Blades

Python for Microcontrollers — Help bring CircuitPython to other languages!

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !

1 Comment

  1. This is very useful information. Please keep the tips coming!

Sorry, the comment form is closed at this time.